Magneto rotors



Feb. 28, 1956 BUCHMANN 2,736,827

MAGNETO ROTORS Filed Jan. 21, 1953 IN V EN TOR.

United States Patent MAGNETO ROTORS Albin Buchmann, Soleure, Switzerland, assignor to Scintilla Ltd., Soleure, Switzerland Application January 21, 1953, Serial No. 332,292

Claims priority, application Switzerland September 23, 1952 Claims. (Cl. 310156) The present invention relates to magnetos.

More particularly, the present invention relates to rotors of magnetos for ignition systems of internal combustion engines. Such rotors may have permanent magnets made of alloys of aluminum, nickel and steel, or aluminum, nickel, cobalt and steel.

Permanent magnets made of the these relatively new alloys possess an appreciably greater coercive force than magnets made of other known material such as, for example, alloys of cobalt and magnetic steel, or the like. By the use of these new alloys it has become possible to manufacture permanent magnets which are much smaller than has previously been possible with a magnet of predetermined coercive force. The use of these alloys of aluminum, nickel and steel, or aluminum, nickel, cobalt and steel for permanent magnets is of itself not new.

Magneto rotors made, for example, of a cobalt-steel alloy, have up to the present time been formed with pressed poles, and a filling of plastic material has been placed between the individual poles to fasten to each pole end laminations of soft iron for deattenuation purposes. This filling also serves as a mounting for the pivots of fly- Weights for the automatic ignition timer. However, these plastic fillings do not possess sufficient mechanical resistance so that as a result a filling of non-magnetic metal replaced the plastic filling material in the further development of the art. This construction, however, has the disadvantage of requiring too much power.

One of the objects of the present invention is to overcome the above disadvantages by providing a magneto rotor of small mass made of the above-mentioned alloys of aluminum, nickel and steel, or aluminum, nickel, cobalt and steel.

A further object of the present invention is to provide a means for connecting to the permanent magnets of such a rotor both the rotor shaft and stacks of laminations of soft iron.

Another object of the present invention is to provide a means for connecting to such a rotor the housing of an ignition timer and the pivot axes of the flyweights thereof.

An additional object of the present invention is to provide a magneto rotor capable of accomplishing all of the above objects while at the same time being made of few, simple, ruggedly constructed parts.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a fragmentary sectional view taken along line I--I of Fig. 2 in the direction of the arrows;

Fig. 2 is an end view of the rotor as seen from the left side of Fig. 1;

Fig. 3 is a side view of a permanent magnet ring constructed in accordance with the present invention;

Fig. 4 is a sectional view taken along line II-II of Fig. 3 in the direction of the arrows;

Fig. 5 is a side view of an end flange of the present invention; and

Fig. 6 is a sectional view taken along line IIIIII of Fig. 5 in the direction of the arrows.

Referring now to the drawings, the rotor of the present invention comprises a pair of flanges 1 made of a nonmagnetic material. Between the two flanges 1 there is located a magnet ring 2 which is coaxial with the circular flanges 1. In the particular example illustrated, the magnet ring 2 is provided with eight poles at its periphery corresponding to the use of the magneto with an eight cylinder engine. For six and four cylinder engines six and four pole magnet rings would be provided, respectively. The magnet ring is closed and the several poles are separated from each other by the grooves 2" so as to form, in the illustrated arrangement of an eight pole ring, a structure corresponding to an arrangement of eight small horseshoe magnets next to each other in a circle. This is illustrated in Fig. 2 by the lines of force K, and Fig. 3 clearly illustrates inner cutouts of the ring 2 which provided the magnet ring with a shape corresponding to the individual magnets.

The outer diameter of the magnet ring is smaller than the diameter of the flanges 1, and the flanges thus form beyond the ring an annular space located about the ring between the flanges and serving as an area in which the stacks of arcuate soft iron laminations 3 may be located respectively next to the poles in such a way that the laminations lie close to the ends of the poles in which position they are fixed by rivets 4 which are arranged about the flange peripheries along a circle and which serve to compress the stacks of laminations and urge the flanges toward each other. The arrangement of soft iron laminations at the pole ends of the permanent magnets is a known means for deattenuating the primary oscillating circuit.

The central portions of the flanges 1 are pressed inwardly in such a way that they each form a substantially hub-like sleeve 1' (Fig. 6). The two flanges are arranged so that the two hubs approach each other to form together a substantially cylindrical wall which serves as a press fit for the rotor shaft 5, the latter having a curved shoulder 5 pressed against one of the flanges 1. Adjacent the other of the flanges 1, the rotor shaft is formed with a shoulder in which a groove 6 extending about the shaft axis is pressed in order to turn a part of the shaft material outwardly and against the rim of the hub of the left flange, as viewed in Fig. 1, so as to fixedly connect the shaft 5 to the flanges.

A centrifugal regulator is built into the magneto for automatically adjusting the ignition timing, and this regulator turns with the rotor and is located within a housing 7 which is fixed to the rotor. In order to fix the housing 7 to the rotor, the pivots 8 for the centrifugal weights of the regulator are lengthened to provide extensions 8' which extend through the magnet ring, as shown in Fig. 2, with each of the extensions 8 located between a pair of the curved portions at the inner opening of the magnet ring 2. The ends of the extensions 8 are peened over to form rivet heads 8" so that the flanges are thereby pressed toward each other and the housing 7 is united with the rotor. The centrifugal weights of the regulator and the other parts thereof are not illustrated in the drawing since they form no part of the present invention.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of magnetos differing from the types described above.

\Vhile the invention has been illustrated and described as embodied in magneto rotors, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

l. A rotor for magnetos and the like, comprising, in combination, a plurality of permanent magnets formed in a closed ring and being located one next to the other, said ring having at its central opening a pluraliy of curved portions conforming to the lines of force of the magnets; a pair of end flanges respectively located against opposite faces of said ring, being made of a non-magnetic material, and being fixedly connected to each other and said ring, a part of one of said flanges forming with a part of another of said flanges a substantially cylindrical bore; a rotor shaft pressed into said bore and being fixed to said flanges; a housing for a centrifugal regulator located next to one of said flanges; and pivot pins located in said housing and having extensions which pass through said flanges and press the latter toward each other, said pins each being located between a pair of said curved portions of said ring.

2. A rotor for magnetos and the like, comprising, in combination, a plurality of permanent magnets formed in a closed ring and being located one next to the other; a pair of end flanges respectively located against opposite faces of said ring, being made of a non-magnetic material, and being fixedly connected to each other and said ring, each of said flanges having a central tubular portion extending into said ring toward the tubular portion of the other of said flanges; a rotor shaft pressed into said tubular portions and being fixed to said flanges; a plurality of stacks of arcuate iron laminations respectively located next to each of the poles of said magnets at the outer face of said ring and between said end flanges; and a plurality of rivets arranged in a circle and passing through said flanges and said stacks of laminations and urging said flanges toward each other to compress said stacks of laminations.

3. A rotor for magnetos and the like, comprising, in

combination, a plurality of permanent magnets formed in a closed ring and being located one next to the other; a pair of end flanges respectively located against opposite faces of said ring, being made of a non-magnetic material, and being fixedly connected to each other and said ring, a part of one of said flanges forming with a part of another of said flanges a substantially continuous sleeve located within said ring; and a rotor shaft pressed into said sleeve, said shaft having an annular shoulder adjacent one of said flanges and bearing against said part thereof and said shaft being formed at the other of said flanges adjacent said part thereof with an annular groove defined on its outer side by an outwardly curved portion of said shaft which is pressed against said part of said other flange.

4. A rotor for magnetos and the like, comprising, in combination, a plurality of permanent magnets formed in closed ring and being located one next to the other, said ring having a central opening formed with a. plurality of curved portions conforming to the lines of force Of, the magnets; a pair of end flanges of non-magnetic material each of which is provided with a central substantially cylindrical hub portion, said flanges being respectively located against opposite faces of said ring and being fixedly connected to each other and said ring with said hubs of said flanges approaching each other and extend.- ing into the interior of said ring; and a rotor shaft pressed into said hubs, said shaft having an annular shoulder bearing against one of said flanges and being formed with an annular groove defined on its outer side by an outwardly curved portion of said shaft which is pressed against the other of said flanges at said hub thereof.

5. A rotor as defined in claim 4 and in which said flanges extend beyond said ring to form an annular space extending about the periphery of said ring and being located between said fianges; and a plurality of stacks of arcuate iron laminations respectively located next to the poles of said magnets in said annular space, said stacks being spaced from each other and being fixed to said flanges.

References Cited in the file of this patent UNITED STATES PATENTS 2,108,924 Quintavalle Feb. 22, 1938 2,257,324 Tognola Oct. 7, 1941 FOREIGN PATENTS 271,592 Great Britain June 2, 1927 523,787 France Apr. 29, 1921 

